In Multi-protocol Label Switching (MPLS) networks, a label may be assigned to represent a set of Forwarding Equivalent Classes (FEC) of packets and a mapping of the label and the FEC may be signaled along the path traversed by the packets. Therefore, the label switched paths are established to forward packets.
Resource reservation protocol (RSVP) is a network control protocol that may be used to enable applications to obtain different quality of service (QoS) for their data flows. However, RSVP is not a routing protocol. Rather, RSVP operates in conjunction with routing protocols.
Resource reservation protocol-traffic engineering (RSVP-TE) is an extension to RSVP that supports resource reservations across an Internet Protocol (IP) network. Generally, RSVP-TE may be used to establish MPLS label switched paths (LSPs) with or without resource reservations, with consideration given to available bandwidth and a number of explicit hops. The LSPs may be setup using explicit routes. A variety of messages and procedures may be used by network elements to inform other network elements of the labels used for MPLS forwarding. The LSPs may be treated as a tunnel, which is tunneling below normal IP routing and filtering mechanisms.
A mechanism for Open Shortest Path First (OSPF) protocol to support multi-topologies (MT) in IP networks, wherein Type of Service (TOS) based metric fields are redefined and used to advertise different topologies is disclosed in P. Psenak, et. al., “Multi-Topology (MT) Routing in OSF,” RFC 4915, June 2007, which is incorporated herein by reference. Separate metrics may be associated for each TOS and may be advertised via protocol information exchange between network elements. The existing OSPF protocol is extended to support network topology changes with Multi-Topology Identifier (MT-ID). Multi-topology information comprises a multi-topology identification and a multi-topology identification metric.
A mechanism within Intermediate System to Intermediate System (IS-IS) to run a set of independent IP topologies for each network topology is disclosed in T. Przygienda, et. al., “M-ISIS: Multi Topology (MT) Routing in Intermediate System to Intermediate Systems (IS-ISs), RFC 5120, February 2008, which is incorporated herein by reference. The existing IS-IS protocol is extended so that advertisements of adjacencies and reachable intermediate system within each topology are performed.
Therefore, there is a need to have systems and methods for supporting multi-topology in MPLS network and extending the RSVP-TE protocol as a signaling protocol in the MPLS network to establish and maintain traffic engineered LSP tunnel within each network topology or across network topologies. The LSP tunnel may need to follow a specific path or to reserve a certain amount of bandwidth to satisfy QoS requirements for the traffic flowing through the LSP tunnel within a specific network topology in an environment of multiple network topologies.